Invisible tool enables new quantum experiments with atoms, molecules, clusters and other nanoparticles

Feb 11, 2013
The three pulsed laser gratings flash for only a few nanosceconds in the experiment. Credit: J. Rodewald/QNP/University of Vienna

Experiments on the quantum wave nature of atoms and molecules have enabled researchers to precisely measure tiny forces and displacements as well as to shed light onto the unexplored zone between the microscopic realm of quantum physics and our everyday world. Physicists around Philipp Haslinger and Markus Arndt at the University of Vienna have now succeeded in constructing a novel matter wave interferometer which enables new quantum studies with a broad class of particles, including atoms, molecules and nanoparticles. These lumps of matter are exposed to three pulsed laser light gratings which are invisible to the human eye, exist only for a billionth of a second and never simultaneously.

The new results are reported in the advanced online issue of .

Matter wave interferometry has a long standing tradition at the University of Vienna, where the first of large molecules has already been observed in 1999. Nowadays scientists are hunting down evidence for the quantum mechanical behavior of increasingly complex constituents of matter. This is done in experiments in which the flying of each particle seems to obtain information about distinct places in space, which are inaccessible according to .

Synchronised laser flashes for quantum interferometry

The quantum team around Markus Arndt of the University of Vienna has now established a novel way of manipulating : the researchers use nanosecond long flashes of laser light to create gratings, three of which form a closed-path interferometer. This scheme allows creating quantum mechanical superposition states, which we do not observe in our macroscopic environment. When precisely synchronized, the fleeting light structures form a device freed from many constraints that limited the measurement precision in earlier machines. "Interferometry in the time-domain with pulsed light gratings will become a central element of quantum experiments with nanoparticles" states Philipp Haslinger who is the first author of the paper.

Viennese prototype with powerful universality

Five students from the University of Vienna have been planning and setting up the device over the past years. The developed prototype is one of a kind: for the first time it allows to investigate the quantum wave nature not only of single molecules, but also of clusters of molecules. During an experiment these particles line up for few nanoseconds in a periodic nanopattern. This structure may serve as a "nanoruler" which enables the detection of tiny external perturbations as well as the precise measurement of small forces and fields.

Explore further: Physicists design quantum switches which can be activated by single photons

More information: Haslinger, P. et al. A universal matter interferometer with optical ionization gratings in the time-domain in Nature Physics (2013).
DOI: 10.1038/NPHYS2542

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2 / 5 (4) Feb 11, 2013
Matter wave interferometry has a long standing tradition at the University of Vienna, where the first quantum interference of large molecules has already been observed in 1999. Nowadays scientists are hunting down evidence for the quantum mechanical behavior of increasingly complex constituents of matter….

This is interesting, unfortunately nowadays we still cannot understand how 'matter wave' was created! Knowing its mechanism would give us more interesting, as below…
2 / 5 (4) Feb 11, 2013
Excellent. We can scale it up to see how TWO cats sealed in a box interfere with each other ;-).
Seriously: The more information like this we have: The more we can grasp the true nature of existence and the space we exist in. Grasping the non localised, waves interacting, nature will get away from a near infinity of multiverses and hocus pocus observer dependent theories of reality.
3.7 / 5 (3) Feb 11, 2013
I went to your page and read your stuff. Your logic falls short. For example this quote:
physicists have explained that electromagnetic waves could be propagated by mutual creation between the changing of electric and magnetic field! But the problem is that both electric and magnetic field are created and changing at the same time from one common time varying current source. So how could they create each other? It violates causality!

No it doesn't. The most common way to create an EM wave is to oscillate an electric dipole. Typically, this involves moving electrons back and forth between 2 radiating elements. As the electrons move between the elements the charge distribution between the elements changes, giving rise to a change in the electric field between the elements. Also, as the electrons move, they form an electric current around which a magnetic field forms. Thus the moving electrons are generating both fields. Causality is not violated in any way.
1.5 / 5 (2) Feb 12, 2013
Well explained CW. The complexity of an EM field/wave (in this video's case it's a photon) is astounding...but a must see for anyone interested in understanding how and why they behave as they do. (PS double slit experiment is explained here so that a kid can understand why we observe what we do)


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